No communications system is perfect

Scarborough public telephone exchange suffered a catastrophic fire. Normal
telephone service didn't exist for a long time for miles around Scarborough.

When the 999 service fails, along with all other telephone services, the
public can't contact any of the emergency services.

The likelihood of such failures is very low. When they do occur, the
problems they cause can be extensive and include loss of life.

When the Falkland Islands were invaded in April 1982, normal communications
failed. The UK government were not aware of the invasion as communications
had been removed. The UK first received reliable details of the invasion
via a radio amateur in the Falklands. The UK radio amateur was also a BBC
journalist. The details were broadcast on BBC News and the UK Foreign Office
contacted the BBC for more details. The BBC News website has details of
this, plus extracts of a recording of the conversation.